The concept of combining several independent mass analyzer instruments into,a single hybrid instrument has been exploited for many years and over many instrument combinations. Ion trap-time-of-flight (IT-TOF) is one of the most recent and potentially useful methods, combining very high sensitivity and fast scanning speed to serve as a generic detector for either high speed chromatography systems (gas, liquid) or electrophoresis systems (capillary). IT-TOF-MS is particularly attractive as a mass analysis method for atmospheric pressure ionization methods, since the ion trap device "buffers" the interaction between the API source and the TOF-MS device, both preserving sensitivity and enhancing mass spectral figures of merit. In the Phase I portion of this research, IT-TOF was demonstrated to have many physical and several analytical properties which distinguish it as a mass analysis tool. In addition to possessing very high sensitivity (by virtue of its ability to "store" ions in free space using radiofrequency waves), the device also retains much of its character as a TOF instrument, allowing detection over an unlimited mass range and acquisition of full mass spectra in quasi real-time. The Phase II portion of this research will focus on the refinement of the technique as an analytical method, concentrating on systematic performance enhancements. A prototype instrument will be built for the demonstration of applications requiring very high sensitivity as well as very high scanning speed in conjunction with either liquid chromatography or capillary electrophoresis. PROPOSED COMMERCIAL APPLICATION: The subject apparatus will be a "second generation" time-of-flight MS interface for high speed separations systems using Electrospray and other atmospheric pressure ionization technologies. It will combine ultra-high sensitivity for sample limited applications, as well as high resolution and high mass accuracy for demanding biological analyses.